Has anyone tried the Manley Pro Flo valves with undercut stems or a similar valve? What was the flow difference between the undercut and straight stem valve?
Phillip

 

I have the Ferrea valves, they look cool as hell, but I cant give you a before and after flow, since more than just the valves were changed. They are suppose to help increase the flow.

 

Phil,
This is what Absolute Speed does to their Manley valves. They undercut them to increase the flow but i'm not sure of the #'s.

 

I've got a set on the shelf now. I've tested them against the REV, and the Ferrea. Not much difference. But that depends on the heads also. I'm getting different results from the different valves in different heads, ie. 5.3, 5.7 and LS6. But if you just asking if they are good. Then the answer is yes. They really are not giving up anything to the other valves in terms of flow.

Chris